1. Field of the Invention
This invention has relation to a human support system to promote sleeping while in a moving structure, and more particularly, to a bed for use by an off duty driver while traveling in a cab of a truck or a semi-trailer tractor.
2. Description of the Prior Art
Large numbers of beds have been devised to allow truckers to rest while over-the-road vehicles are being driven by on duty drivers. A number of such structures have been patented.
A preliminary search was conducted on an early form of the present invention, and the following more or less pertinent patents were cited.
U.S. Pat. No. 4,144,601, granted on Mar. 20, 1979 to Anderson et al, discloses a bed in which the vertical shocks are taken up by air cushions and scissor legs. Fore and aft shocks in the direction of truck movement (transverse movement with respect to a person on the bed) are absorbed by movement of a top frame along a base frame to allow the top frame to come into contact with opposed compression coil springs. As seen in FIG. 5 of Anderson et al, axes of vertical movement and of movement on the longitudinal axis of the truck are provided. No provision is made to cushion against component of motion at right angles to the direction of the primary movement of the truck.
U.S. Pat. No. 4,497,078 granted on Feb. 5, 1985 to Vogel et al shows a bed wherein air bags and accumulators ar used to cushion fore and aft movement of the truck and other air bags and accumulators are used to cushion vertical movement. No provision is made for handling lateral or transverse shocks to the sleeping person.
U.S. Pat. No. 4,107,797 granted on Aug. 22, 1978 to Maxwell shows a bed with an intermediate frame which rolls in the fore and aft direction of truck movement on a base frame and is biased to tend to stay in a middle position when not stressed. Vertical movement of an upper pallet frame toward the intermediate frame is cushioned by a horizontally positioned shock absorber. There is no provision for absorbing motion transverse to the direction of movement of the truck.
U.S. Pat. No. 3,612,599 granted on Oct. 12, 1971 to Sternberg shows a bed in which a horizontal base frame is mounted on springs to take up the vertical shock. A horizontal intermediate frame is supported on rollers running on the base frame, and springs are positioned to absorb shocks due to fore and aft movement of the intermediate frame in the direction of movement of the truck. These opposed coil springs tend to center the pallet in front and rear direction of truck movement. No provision is made for absorbing side to side components of shock.
Of less pertinence are the following patents.
U.S. Pat. No. 3,524,673 granted on Aug. 19, 1970 to Cramer et al discloses a pallet supported on a base frame by eight generally horizontal springs between the pallet and the frame. Because the pallet must be supported in substantial clearing relationship with respect to the outer frame, and because the space for such beds in truck cabs is extremely limited, the size of the bed available to the sleeping trucker is quite limited. Also, since this Cramer structure was invented prior to Apr. 8, 1968 and has been patented since August of 1970, it has not been generally adopted to solve the problem which occasioned its development. For example, all of the prior art patents set out above, and many of the patents cited below, were developed and patented after the Cramer patent was part of the prior art. Neither the patent to Cramer nor any other prior art patent found general acceptance before the present invention.
U.S. Pat. No. 3,698,022 granted on Oct. 17, 1972 shows a more or less standard "Army cot" design supported on four posts by inclined tension coil springs. A vertical spring 42 or "shock absorber (dashpot)" extends from a horizontal bar to one of the pallet frame ends to absorb vertical shock movement. Because the conventional "generally rectangular section of wire mesh 9" comes right up to the sides and ends of the rectangular frame, there is little, if any, ability to absorb either fore and aft, or side to side components of shock.
U.S. Pat. No. 3,285,652 granted on Nov. 15, 1966 to Coup shows the use of rubber bands 20 to support a pallet frame on a base. Vertical tracks and rollers prevent fore and aft movement and make no provision for components of shock in side to side relation to movement of the truck along the highway.
U.S. Pat. No. 3,141,178 granted on July 21, 1964 to Campbell utilizes springs under a pallet to absorb vertical shock. Vertical guides 70 and rollers 74 resist any horizontal movement in fore and aft or side by side direction.
U.S. Pat. No. 3,882,558 granted May 13, 1975 to Christensen shows downward movement of a top pallet frame 30 with respect to a lower base frame 20 which causes drums 20 to rotate in opposite directions, the bottom surface of each drum moving toward that of the other. Shock absorber 50 is attached to lines 54 and 55 wrapped around the top of the drum surfaces, so shock absorber 50 cushions and limits downward movement of the pallet frame. There appears to be no provision to lessen shocks in directions fore and aft or side by side of truck movement.
U.S. patents cited during the search, but believed to be less pertinent include: U.S. Pat. Nos. 3,298,043 granted on Jan. 18, 1967 to Muller et al; 4,443,034 granted on Apr. 17, 1984 to Begs; 4,603,900 granted on Aug. 5, 1986 to Dodgen; 4,319,778 granted on Mar. 16, 1982 to Leonard et al; 3,402,960 granted on Sept. 24, 1968 to Erke; 3,588,168 granted on June 28, 1971 to Frotzheim et al; 3,879,081 granted on Apr. 22, 1975 to Hockley; 4,215,S99 granted on Aug. 5, 1980 to Schmidt et al; and 4,221,424 granted on Sept. 9, 1980 to Eiserman et al.
What was needed before the present invention was a truck bed suspension which would cushion a sleeping person against vertical shocks of truck or other vehicle movement, against components of shock in a horizontal direction whether those components were in line with the direction of movement of the truck, were transverse to the direction of movement of the truck, or were anywhere in between those directions; and which would give the feeling of "free floating" on a horizontal bed in space.
Neither the inventor nor those in privity with him are aware of any prior art closer than that discussed above; nor are they aware of any prior art which anticipates the claims herein.